Abstract
Energy efficiency is low with the control of the hydraulic system using the pressure loss of throttle valves widely used in current construction machinery but if energy regeneration by PWM control switching high and low pressure source at high speed is used, improvement in efficiency can be expected. We proposed response analysis method considering nonlinear pressure loss of valve, elasticity of oil, influence of cylinder and load on hydraulic system using PWM control. First, we showed response analysis method with one degree of freedom system model neglecting elasticity of fluid, and showed a method to handle valve nonlinear pressure loss approximately. Next, we proposed a response analysis method using modal analysis based on the theoretical solution and Fourier series expansion, and showed how the load and fluid elasticity influences the response using the proposed method.
